I have a 96 F150 4X4 with a 5.8 and I'm having shift issues with my transmission. The trans is very reluctant to upshift. Unless I am extremely gentle with the gas pedal it won't shift up unless I let off of the gas. Shifts are usually hard when they do happen, and it does that in all the gears. I have been working overseas for the last year and a half and my parents have driven my truck less than I would have liked them to while I was gone. I did change the fluid about a year before I went overseas and it still looks and smells new. The level is good also. I checked the codes it is throwing and I'm getting P1120 and P0122. Those both indicate a throttle position sensor out of range. Could a TPS cause shift issues like that, or am I looking at two different problems at the same time? The engine starts, idles, and runs fine otherwise.

FWIW, when I first arrived home about a month ago, we had to tow the truck in to the shop for a no spark condition that I couldn't diagnose myself. According to the shop it was ,IIRC, a bad Hall effect sensor on the distributor. They replaced the entire distributor since the truck has a lot of miles on it and I didn't want to have to worry about the 24 year old drive gear failing somewhere down the road. Once my truck was running again, I noticed a hard shift every now and then, but things didn't get bad until I took a road trip over the weekend. I had a nervous drive back home yesterday.

Thanks in advance for the help.

 

Yes, the TPS is a critical computer input for determining trans operation. Note, there is only one computer in this vehicle and it controls both engine and trans.

 

Thanks, since my tools are all packed up and buried in storage it looks like the shop is getting another check from me. I'm glad to see that it will be a small check though and not a transmission rebuild sized check.